<PAGE>   1
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549


                                  SCHEDULE 13G

                    Under the Securities Exchange Act of 1934

                                (Amendment No.4)



                                  NOVAVAX, INC.
        ----------------------------------------------------------------
                                (Name of Issuer)


                          COMMON STOCK, $.01 PAR VALUE
        ----------------------------------------------------------------
                         (Title of Class of Securities)


                                   670002 10 4
        ----------------------------------------------------------------
                                 (CUSIP Number)






Check the following box if a fee is being paid with this statement. [ ] (A fee
is not required only if the reporting person: (1) has a previous statement on
file reporting beneficial ownership of more than five percent of the class of
securities described in Item 1; and (2) has filed no amendment subsequent
thereto reporting beneficial ownership of five percent or less of such class.)
(See Rule 13d-7.)


                         (CONTINUED ON FOLLOWING PAGES)



                               PAGE 1 OF 13 PAGES

                         THE EXHIBIT APPEARS ON PAGE 11



<PAGE>   2




                              CUSIP NO. 670002 10 4
- -------------------------------------------------------------------------------

(1)      Name of Reporting Person
         S.S. or I.R.S. Identification No. of Above Person
                        Charles B. Ganz
         ---------------------------------------------------------------------- 

(2)      Check the Appropriate Row if a Member of a Group
                  (a)
                     -----------------------------------------------------------
                  (b)
                     -----------------------------------------------------------

(3)      SEC Use Only
                     ----------------------------------------------------------

(4)      Citizenship or Place of Organization                 U.S.A.
                                              ---------------------------------

Number of                   (5) Sole Voting Power            721,968*
Shares Bene-                                      -----------------------------
ficially      
Owned by Each  (6)     Shared Voting Power                         0            
Reporting                                      --------------------------------
                                                                               
               (7)     Sole Dispositive Power                721,968*          
                                               --------------------------------

Person With
           --------------------------------------------------------------------
               (8)     Shared Dispositive Power                    0
                                               --------------------------------
                                               
(9)      Aggregate Amount Beneficially Owned by Each Reporting Person
                                   721,968*
         ----------------------------------------------------------------------

(10)     Check if the Aggregate Amount in Row (9) Excludes Certain
         Shares                                                      
                ---------------------------------------------------------------
(11)     Percent of Class Represented by Amount in Row (9)      7.26%
                                                            -------------------

(12)     Type of Reporting Person               IN
                                 ----------------------------------------------

*The Reporting Person disclaims beneficial ownership of these shares. See 
 Item 4.

                               PAGE 2 OF 13 PAGES



<PAGE>   3




                              CUSIP NO. 670002 10 4
- -------------------------------------------------------------------------------
(1)      Name of Reporting Person
         S.S. or I.R.S. Identification No. of Above Person
                        Ganz Capital Management, Inc.
         ----------------------------------------------------------------------

(2)      Check the Appropriate Row if a Member of a Group
                  (a)
                     ----------------------------------------------------------
                  (b)
                     ----------------------------------------------------------

(3)      SEC Use Only
                     ----------------------------------------------------------

(4)      Citizenship or Place of Organization                 Delaware
                                                   ----------------------------

Number of                   (5) Sole Voting Power              630,768
Shares Bene-                                          -------------------------
ficially                                                        
Owned by Each               (6)     Shared Voting Power              0
Reporting                                                   -------------------

                            (7)     Sole Dispositive Power     630,768
                                                            -------------------
Person With
                            (8)     Shared Dispositive Power         0
                                                            -------------------

(9)      Aggregate Amount Beneficially Owned by Each Reporting Person
                                630,768
         ----------------------------------------------------------------------

(10)     Check if the Aggregate Amount in Row (9) Excludes Certain
         Shares                    *
               ----------------------------------------------------------------

(11)     Percent of Class Represented by Amount in Row (9)   6.35%
                                                            -------------------

(12)     Type of Reporting Person               IA
                                 ----------------------------------------------


*See Item 4, and the notes thereto.

                               PAGE 3 OF 13 PAGES



<PAGE>   4



                              CUSIP NO. 670002 10 4
- -------------------------------------------------------------------------------
(1)      Name of Reporting Person
         S.S. or I.R.S. Identification No. of Above Person
                        The Probitas Fund, L.P.
         ----------------------------------------------------------------------
(2)      Check the Appropriate Row if a Member of a Group
                  (a)
                     ----------------------------------------------------------
                  (b)
                     ----------------------------------------------------------
(3)      SEC Use Only
                     ----------------------------------------------------------
                                                         
(4)      Citizenship or Place of Organization                 Delaware
                                              ---------------------------------

Number of                   (5) Sole Voting Power               52,900
Shares Bene-                                      -----------------------------
ficially    
Owned by Each               (6)     Shared Voting Power              0
Reporting                                               -----------------------

                            (7)     Sole Dispositive Power      52,900
                                                          ---------------------
Person With
                            (8)     Shared Dispositive Power         0
                                                          ---------------------

(9)      Aggregate Amount Beneficially Owned by Each Reporting Person
                                  52,900
         ----------------------------------------------------------------------

(10)     Check if the Aggregate Amount in Row (9) Excludes Certain
         Shares                  *
         ----------------------------------------------------------------------

(11)     Percent of Class Represented by Amount in Row (9)       0.53%
                                                           --------------------

(12)     Type of Reporting Person               PN
                                 ----------------------------------------------


*See Item 4, and the notes thereto.

                               PAGE 4 OF 13 PAGES



<PAGE>   5



                              CUSIP NO. 670002 10 4
- -------------------------------------------------------------------------------
(1)      Name of Reporting Person
         S.S. or I.R.S. Identification No. of Above Person
                        The Probitas Offshore Fund, L.P.
         ----------------------------------------------------------------------

(2)      Check the Appropriate Row if a Member of a Group
                  (a)
                     ----------------------------------------------------------
                  (b)
                     ----------------------------------------------------------
(3)      SEC Use Only 
                     ----------------------------------------------------------
(4)      Citizenship or Place of Organization            Cayman Islands
                                             ----------------------------------
Number of                   (5) Sole Voting Power                38,300
Shares Bene                                      ------------------------------
ficially-
Owned by Each               (6)     Shared Voting Power               0
Reporting                                              ------------------------

                            (7)     Sole Dispositive Power       38,300
                                                          ---------------------
Person With
                            (8)     Shared Dispositive Power          0
                                                            -------------------
(9)      Aggregate Amount Beneficially Owned by Each Reporting Person
                                   38,300
         ----------------------------------------------------------------------
(10)     Check if the Aggregate Amount in Row (9) Excludes Certain
         Shares                  *
               ----------------------------------------------------------------
(11)     Percent of Class Represented by Amount in Row (9)        0.39%
                                                           --------------------

(12)     Type of Reporting Person               PN
                                 ----------------------------------------------


*See Item 4, and the notes thereto.

                               PAGE 5 OF 13 PAGES



<PAGE>   6



                              CUSIP NO. 670002 10 4
- -------------------------------------------------------------------------------
(1)      Name of Reporting Person
         S.S. or I.R.S. Identification No. of Above Person
                        Probitas Advisors, Inc.
         ----------------------------------------------------------------------
(2)      Check the Appropriate Row if a Member of a Group
                  (a)
                     ----------------------------------------------------------
                  (b)
                     ----------------------------------------------------------
(3)      SEC Use Only 
                     ----------------------------------------------------------
(4)      Citizenship or Place of Organization                  Delaware
                                             ----------------------------------
Number of                   (5) Sole Voting Power                91,200
Shares Bene                                      ------------------------------
ficially-
Owned by Each               (6)     Shared Voting Power               0
Reporting                                              ------------------------

                            (7)     Sole Dispositive Power       91,200
                                                          ---------------------
Person With
                            (8)     Shared Dispositive Power          0
                                                            -------------------
(9)      Aggregate Amount Beneficially Owned by Each Reporting Person
                                  91,200
         ----------------------------------------------------------------------
(10)     Check if the Aggregate Amount in Row (9) Excludes Certain
         Shares                 *
               ----------------------------------------------------------------
(11)     Percent of Class Represented by Amount in Row (9)        0.92%
                                                          ---------------------
(12)     Type of Reporting Person               CO
                                 ----------------------------------------------


*See Item 4, and the notes thereto.

                               PAGE 6 OF 13 PAGES



<PAGE>   7




ITEM 1(A).        NAME OF ISSUER

                      The Issuer is NOVAVAX, INC.. ("NOX").

ITEM 1(B).        ADDRESS OF ISSUER'S PRINCIPAL EXECUTIVE OFFICES

                           The Issuer's principal executive offices are located
                  at 12601 Twinbrook Parkway, Rockville, Maryland 20852.


ITEM 2(A).        NAME OF PERSONS FILING

                           This Schedule 13G is being filed on behalf of Charles
                  B. Ganz ("Ganz"), Ganz Capital Management, Inc. ("GCM"), The
                  Probitas Fund, L.P. (the "Fund"),Probitas Advisors, Inc.
                  ("Advisors")and The Probitas Offshore Fund, L.P. ("Offshore
                  Fund").

ITEM 2(B).        ADDRESS OF PRINCIPAL BUSINESS OFFICE OR, IF NONE,
                  RESIDENCE

                           The principal business office of Ganz, GCM, the Fund
                  and Advisors is 2875 N.E. 191st Street, Penthouse I, North
                  Miami Beach, Florida 33180. The principal business office of
                  Offshore Fund is British American Centre, P.O. Box 513 GT, Dr.
                  Roy's Drive, George Town, Grand Cayman, Cayman Islands,
                  British West Indies.

ITEM 2(C).        CITIZENSHIP

                           Ganz is a United States citizen. GCM and Advisors are
                  Delaware corporations. The Fund is a Delaware limited
                  partnership. Offshore Fund is a Cayman Islands limited
                  partnership.

ITEM 2(D).        TITLE OF CLASS OF SECURITIES

                           This Statement relates to the Common Stock, par value
                  $ .01 per share (the "Common Stock"), of NOX.

ITEM 2(E).        CUSIP NO.

                           NOX's CUSIP No. is 670002 10 4.

ITEM 3.           IF THIS STATEMENT IS FILED PURSUANT TO RULES 13D-1(B), OR 
                  13D-2(B), CHECK WHETHER THE PERSON FILING IS A

                               PAGE 7 OF 13 PAGES



<PAGE>   8




                           (a) [ ] Broker or Dealer registered under Section 15
                  of the Act

                           (b) [ ] Bank as defined in Section 3(a)(6) of the Act

                           (c) [ ] Insurance Company as defined in Section
                  3(a)(19) of the Act

                           (d) [ ] Investment Company registered under Section 8
                  of the Investment Company Act

                           (e) [X] Investment Adviser registered under Section
                  203 of the Investment Adviser Act of 1940

                           (f) [ ] Employee Benefit Plan, Pension Fund which is
                  subject to the provisions of the Employee Retirement Income
                  Security Act of 1974 or an Endowment Fund; see Rule
                  13d-1(b)(1)(ii)(F)

                           (g) [ ] Parent Holding Company, in accordance with
                  Rule 13d-1(b)(1)(ii)(G) (Note: See Item 7)

                           (h) [ ] Group, in accordance with Rule 13d-
                  1(b)(1)(ii)(H)


ITEM 4.  OWNERSHIP

         SEE ATTACHED SPREADSHEET, LABELED EXHIBIT A (PAGE 11 OF 13), FOR A
         LISTING OF OWNERSHIP.


         (1) The Reporting Person disclaims beneficial ownership with respect to
these shares.

         (2) Due to the fact that GCM, Advisors, the Fund and Offshore Fund are
under common control, GCM may be deemed to beneficially own the 52,900 shares
owned of record by the Fund and the 38,300 owned by Offshore Fund. The Reporting
Person disclaims beneficial ownership with respect to these shares.

         (3) Due to the fact that GCM, Advisors and the Fund are under common
control, Advisors, the Fund and Offshore Fund may be deemed to beneficially own
the 630,768 shares owned of record by GCM. The Reporting Persons disclaim
beneficial ownership with respect to these shares.




                               PAGE 8 OF 13 PAGES



<PAGE>   9

ITEM 5.  OWNERSHIP OF FIVE PERCENT OR LESS OF A CLASS


                  If this Statement is being filed to report the fact that as of
         the date hereof the Reporting Person has ceased to be the beneficial
         owner of more than five percent of the class of securities, check the
         following [ ].

ITEM 6.  OWNERSHIP OF MORE THAN FIVE PERCENT ON BEHALF OF ANOTHER PERSON

                  GCM is a registered investment adviser, investing and managing
         funds for its clients, which include individuals, employee benefit
         plans, corporations, limited partnerships, charitable foundations and
         trusts. GCM beneficially owns 6.35% of NOX's issued and outstanding
         shares of Common Stock, on behalf of its clients, in separate accounts
         established for each client. Each client owns his, her or its account,
         and thereby has the right to receive and the power to direct the
         receipt of dividends, if any, from the Common Stock.

                  Advisors is a registered investment adviser, investing and
         managing funds for its clients, which include individuals, employee
         benefit plans, corporations, limited partnerships, charitable
         foundations and trusts. Advisors beneficially owns 0.92% of NOX's
         issued and outstanding shares of Common Stock, on behalf of their
         clients, in separate accounts established for each client. Each client
         owns his, her or its account, and thereby has the right to receive and
         the power to direct the receipt of dividends, if any, from the Common
         Stock.

                  The Fund and Offshore Fund are limited partnerships
         established in Delaware and the Cayman Islands respectfully. Fund and
         Offshore Fund are clients of Advisors, a registered investment adviser.
         Fund and Offshore Fund are authorized to invest in any class or type of
         security or other investment. Advisors acts as General Partner for Fund
         and as Investment General Partner for Offshore Fund. Fund beneficially
         owns 0.53% of NOX's issued and outstanding common stock. Offshore Fund
         beneficially owns 0.39 % of NOX's issued and outstanding common stock.

ITEM 7.  IDENTIFICATION AND CLASSIFICATION OF THE SUBSIDIARY WHICH ACQUIRED THE
         SECURITY BEING REPORTED ON BY THE PARENT HOLDING COMPANY

         Not applicable.



                               PAGE 9 OF 13 PAGES



<PAGE>   10



ITEM 8.  IDENTIFICATION AND CLASSIFICATION OF MEMBERS OF THE GROUP

                  Not applicable.

ITEM 9.  NOTICE OF DISSOLUTION OF GROUP

                  Not applicable.

ITEM 10.  CERTIFICATION

                  By signing below I certify that, to the best of my knowledge
         and belief, the securities referred to above were acquired in the
         ordinary course of business and were not acquired for the purpose of
         and do not have the effect of changing or influencing the control of
         the issuer of such securities and were not acquired in connection with
         or as a participant in any transaction having such purposes or effect.



















                               PAGE 10 OF 13 PAGES



<PAGE>   11






                                    EXHIBIT A



<TABLE>
<CAPTION>

                               AMOUNT    
                            BENEFICIALLY       PERCENT OF          POWER TO VOTE          POWER TO DISPOSE
     REPORTING PERSON          OWNED             CLASS          SOLE      SHARED         SOLE      SHARED
<S>                           <C>      <C>       <C>     <C>     <C>          <C>         <C>          <C>
Charles B. Ganz               721,968  (1)       7.26%   (2)     721,968      0           721,968      0
Ganz Capital Management, Inc. 630,768  (1)       6.35%   (2)     630,768      0           630,768      0
Probitas Advisors, Inc.        91,200  (1)       0.92%   (2)      91,200      0            91,200      0
The Probitas Fund, L.P.        52,900  (1)       0.53%   (2)      52,900      0            52,900      0
The Probitas Offshore Fund,    38,300  (1)       0.39%   (2)      38,300      0            38,300      0
 L.P.                       ==============               ===              =======                  ========
</TABLE>

     
(1) The reporting person disclaims beneficial ownership of these shares.
(2) Calculated on the basis of 9,937,936 shares outstanding as of 12/31/96




  





                               PAGE 11 OF 13 PAGES



<PAGE>   12




                                   SIGNATURES


         After reasonable inquiry and to the best of our knowledge and belief,
we certify that the information set forth in this statement is true, complete
and correct.


       January 17, 1997
- --------------------------

                           /s/ Charles B. Ganz
                          --------------------------------------
                            CHARLES B. GANZ



                          GANZ CAPITAL MANAGEMENT, INC.


                          By:  /s/ Charles B. Ganz
                              -----------------------------------
                              Charles B. Ganz, President



                          THE PROBITAS FUND, L.P.


                          By:    Probitas Advisors, Inc.,
                                 General Partner


                          By:  /s/ Charles B. Ganz
                              -----------------------------------
                              Charles B. Ganz, President



                          PROBITAS ADVISORS, INC.


                          By:  /s/ Charles B. Ganz
                              -----------------------------------
                              Charles B. Ganz, President




                               PAGE 12 OF 13 PAGES



<PAGE>   13


                                    EXHIBIT A

                      AGREEMENT TO FILE JOINT SCHEDULE 13G


            Pursuant to Rule 13d-1(f)(i), the undersigned hereby consent to the
joint filing of a single statement on their behalf.



       January 17, 1997
- --------------------------

                           /s/ Charles B. Ganz
                          --------------------------------------
                            CHARLES B. GANZ



                          GANZ CAPITAL MANAGEMENT, INC.


                          By:  /s/ Charles B. Ganz
                              -----------------------------------
                               Charles B. Ganz, President



                          THE PROBITAS FUND, L.P.


                          By:    Probitas Advisors, Inc.,
                                 General Partner


                          By:  /s/ Charles B. Ganz
                              -----------------------------------
                              Charles B. Ganz, President



                          PROBITAS ADVISORS, INC.


                          By:  /s/ Charles B. Ganz
                              ------------------------------------
                               Charles B. Ganz, President



                               PAGE 13 OF 13 PAGES